For forming color photographic images, three kinds of color forming photographic couplers, namely yellow, magenta, and cyan color forming couplers are contained in light-sensitive silver halide emulsion layers, and the layers are exposed and then processed by a color developer containing a color developing agent. In this development course, the oxidation product of the aromatic primary amine causes coupling reactions with the couplers to give colored dyes and in this case, it is necessary to give color density as high as possible in a limited developing time.
The purpose of obtaining high color density is usually attained by using couplers having a coupling speed as high as possible, by using silver halide emulsions which are liable to be developed and provide large amount of developed silver per unit coating amount, or by using a color developer showing a high developing speed.
For increasing the developing speed of a silver halide emulsion, it can be easily considered to increase the content of silver chloride in the silver halide but the increase of the content of silver chloride causes a faults that the sensitivity is reduced and fog is liable to form. Also, it may be considered to increase the aforesaid content of silver chloride or strengthen the chemical sensitization for increasing the amount of developed silver but in this case also, there is a fault that fog is liable to form. Furthermore, it is a means for quickening the development to reduce the grain size in a silver halide emulsion but such an attempt has a fatal fault that the sensitivity is lowered. Also, a process of using a silver chloride emulsion is described, for example, in unexamined Published Japanese Patent Application Nos. 95345/83, 232342/84, and 19140/85, but there is a problem that the control of the gradation is difficult.
On the other hand, on a color developer, various attempts have hitherto been made for increasing the development. In these attempts, various additives have been investigated for increasing the permeation of a color developing agent into color coupler-dispersed oil drops to accelerate coloring, and in particular, a process of quickening the color development by adding benzyl alcohol to a color developer has been widely used for the processing of color photographic light-sensitive materials, particularly color photographic papers since the process has a high coloring accelerating effect.
However, since benzyl alcohol has low water-solubility, in the case of using benzyl alcohol it is required to use a solvent such as diethylene glycol, triethylene glycol, alkanolamine, etc. However, since the aforesaid compounds including benzyl alcohol give high BOD and COD, which are pollution-giving values, it is preferred not to use benzyl alcohol for the purpose of reducing the pollution load.
Furthermore, even in the case of using the aforesaid solvent, it takes a long period of time to dissolve benzyl alcohol in the solvent and hence for the purpose of reducing the working load for preparing the liquid, it is better not to use benzyl alcohol.
Also, when benzyl alcohol is carried in a bleach bath or a blix bath, which is a post-bath, it causes the formation of leuco dyes of cyan dyes, which results in the reduction of color density. Furthermore, the entrance of benzyl alcohol delays the washing out speed of the developer components, which sometimes gives bad influences on the image storage stability of processed light-sensitive materials. Accordingly, it is better not to use benzyl alcohol in the reasons described above.
A color development has generally been performed in from 3 minutes to 4 minutes but it has been desired to further shorten the processing time with the recent desirement for shortening the time for delivery of finished products and the reduction of laboratory works.
However, in the case of omitting benzyl alcohol which is a coloring accelerator and shortening the developing time, a severe reduction in color density inevitably occurs.
For solving the problems, even when various kinds of color development accelerators (for example, compounds as described in U.S. Pat. Nos. 2,950,970, 2,515,147, 2,496,903, 2,304,925, 4,038,075, and 4,119,462, British Patent Nos. 1,430,998, and 1,445,413, Unexamined Published Japanese Patent Application Nos. 15831/78, 62450/80, 62451/80, 62452/80, and 62453/80, Japanese Patent Publication Nos. 12422/76 and 49728/80) are employed together, sufficient color density has not yet been obtained.
Also, even when techniques of incorporating 3-pyrazolidones (for example, techniques as described in Unexamined Published Japanese Patent Application Nos. 26338/85, 158444/85, and 158446/85) are used, the use of such a technique is accompanied by a disadvantage that the sensitivity is reduced and fog forms in the case of storing the color photographic materials in unexposed state.
Furthermore, even when techniques of incorporating color developing agents (for example, techniques as described in U.S. Pat. Nos. 3,719,492, 3,342,559, and 3,342,597, Unexamined Published Japanese Patent Application Nos. 6235/81, 16133/81, 97531/82, and 83565/82) are used, the use of such a technique is accompanied by a disadvantage that the color development is delayed and fog forms, and the techniques are improper.
Still further, as a process of completely removing benzyl alcohol from a color developer or a process of reducing the content of benzyl alcohol in a color developer, it is proposed to use a silver chlorobromide core/shell type emulsion containing 50 to 97 mol% of silver bromide, the content of silver bromide in the surface portion (shell portion) thereof being higher than that in the inside (core portion) thereof in Unexamined Published Japanese Patent Application No. 48755/84 or to employ relatively small silver halide grains of up to 0.6 .mu.m and further to incorporate phenidone or a derivative thereof in light-sensitive material in Unexamined Published Japanese Patent Application No. 26339/85, which also teaches the use of a monodispersed emulsion having a variation coefficient of up to 0.15. However, these propositions are yet insufficient in the points of the color density obtained, etc., for processing light-sensitive materials in a short developing time of up to 2 minutes and 30 seconds using substantially no benzyl alcohol for the color developer.
The first object of this invention is, therefore, to provide a color image-forming process giving high color density in a short period of time using a color developer substantially free from benzyl alcohol.
The second object of this invention is to provide a color image-forming process giving less fog and with quick development